<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>demo</title>
</head>
<style>
    html,body{
        width: 100%;
        height: 100%;
    }
</style>
<body>
<!--<embed width="100%" height="100%" name="plugin" id="plugin" src="" type="application/pdf" internalinstanceid="3">-->

<form action="javascript:void(0)">
    <select name="" id="">
        <option value="">1</option>
        <option value="">2</option>
        <option value="">3</option>
    </select>
    <button type="submit">提交</button>
</form>
</body>
</html>